Glucoamylase Enzyme Production by Aspergillus niger Fermentation and Cassava Starch as Substrate

Abstract

Glucoamylase enzyme is widely used in many industries. In Indonesia, this enzyme is needed increasingly for recent years and nowadays still imported with expensive cost. To overcome this problem, an alternative cheaper process for enzyme production was developed. It was conducted by an experimental investigation via batch fermentation by Aspergillus niger fungi with cassava starch as substrate. The fermentation broth in a 500-ml flask was incubated and shaken at room temperature and the substrate was varied at different concentrations. For several certain time interval, the broth was sampled and therefore its enzyme activity, dry cell weight, and remaining substrate concentration was analyzed. This research showed that the optimum condition for fermentation was obtained at substrate concentration of 9% and initial pH of 6. At this condition, the fermentation after 7 days produced glucoamylase enzyme with activity of 0.1355 Unit/ml. In addition, this experiment resulted in the kinetics parameters including saturation constant (KS) of 0.287 g/100 ml, maximum growth rate (max) of 4.127day-1, and enzyme-to-substrate productivity (YP/S) of 0.3826 Unit/g starch.